Grindina machine



Feb. 3, 1931. A. J. BERG ,5

GRINDING MACHINE Original Filed Aug, 16, 1927 fllgllullllllllllunn'g rINVENTOR lfi'ed I Berg- Patented Feb. 3, 1931 PATENT oFFIcE ALFRED I.BERG, OF PORTSMOUTH, NEW HAMPSHIRE Gamma moms Original application filedAugust 16,

My invention relates to grinding machines and particularly tomachinesiidapted to re-" face valve seats by minding and truingsame topredetermined limits.

' It has for its general objects the provision of a power-drivengrinding wheel and means;

for mounting same concentric with the axis of the cyiinder or the likeelement uponwhich the valve is seated; and the provision of meanswhereby the application of the grinding wheel to the valve seat ismanually controlled and the depth of metal to be removed .isautomatically limited by ready preadjustment of a precision gauge.

With the foregoing and other and more particular objects in view, ashereinafter pointed out, my invention consists of the features ofimprovement next herein set forth and described and illustrated in theaccompanying drawings forming a part of this specification, and in whichis shown that embodiment at present preferred by me as that bestcalculated to attain the features of advantage of my invention. In thesedrawings:

Figure 1 is an elevational view, partly 1n section, of a grindingmachine operatlvely associated with the valve seatrof an enginecylinder;

Fig. 2 isja planview thereof;

Fig. 3 is a plan view of an attachment for dressing the grinder wheel;and v Fig. 4 is a sectional view of a' modification. 'Like referencenumerals indicate like parts throughout'the several figures, 1n whlch 1is the fixture which supports the valve seat- 3 and contains the guide 2for the stem ofthe valve cooperating therewith. The valve is A motor 4suitably connectedto a'power source has a shaft 5 on which is mountedthe emery or like surfaced grinding wheel 6. ,T he motor is mounted upona base -7 to whlch spindle 10 is screwed into the base 7, or otherwiserigidly aflixed thereto, and errtends downwardly into the valve stemguide or bore 2, to whose internal diameter it is adapt ed by thecylindrical bushing 11 screwed of course removed when the seat isground.

it is clamped by the yoke 8 and bolts 9. A Y

1987, No. 213,277. Divided and this application filed August 19, 1929.Serial No. 887,071.

upon the spindle. The adapter bushing is free to turn in the bore. 1 1

A knurled micrometer thimble 13 consisting of a transversely split ringwhose butting ends are drilled at 31 and threaded for a clampmg screw17, is threaded for engagement on the spindle 10. The thimble carriesthe scale markings 14 which are adapted to register, as the thimble isrevolved, with the scale markings 15'upon the flange, 16 depending-fromand integral with the motor base 7. Bymeans of the clamping screw 17passing through the threaded hole 31 in the ends of the split-ringforming the thimble of the micrometer,-the thimble may be clamped to thespindle, whereby the micrometer thimble turns with the spindle andmaintains its adjustment for the depth of cut desired, as

be later described. 1

The grinder is preferably provided wit a-dressing attachment consistingof the support 18 held by the clamp 19 to the yoke 8 by screws and nuts33. A head 20 on the support received the threaded bolt 21 havi g thewing-nut 22, the bolt 21 retaining 't e; thrust block 23 against thehead 20.. The

frame members 24 extend from the head 20- 26 carried by the thrust block23 and engaging the member 25. The slide has the series of holes 27adapted to receive, as. required, the dressing tool 28 having thediamond point 29. The tool 28 isheld by a set screw- 30.v As will beunderstood, the angle of the slide holder and dressin tool is adjustedaccording to the conical ace of the grinding wheel, which in' turn isdetermined by the desired bevel of the valve seat.

The method of utilizing my improved grinder is as follows a Acylindrical bushing adapted to the bore of the cylinder in slidingcontact is screwed upon the spindle. These are next inserted in thevalve stem bore until the micrometer thimble rests upon the top of thewall 12 of the bore, the thimble being free to turn on its thread andadjusted to engage the wall of the bore before the grinder en a thevalve seat. The micrometer thimb e is then 25 contmueduntll the grlnderremoves no more rotated about the spindle in a direction to lower themotor base until the grinder wheel approaches the valve seat. The motoris then energized and further lowered until' the grinder contacts withthevalve seat, and a spark is struck by theirfrlctlon. The m1 crometergauge is then read and from themdicated point is calculated the desiredsetting, the diiference being the thlckness of the metal to, be removed.,The motor is then stopped and the micrometer thimble rotated in thereverse direction, while holding the motor stationary? with the'wheel111 contact with the valve face, to a degree representing the thicknessof the cut, as indicated by the micrometer reading, and there set bythetension-screw, whereby the thimble is held against further rotationupon the spindle. The lower face 32 of'the thimble will then beseparated from the upper face 12 of the cylinder wall by the depth ofthe cut to be made. The motor head is then manually revolved withltherotating grinder in cutting engagement with the valve seat, the motorbeing, again energized and this cuttmg is metal. Whenever the grinderhas cut to the predeter mined depth, it is automatically prevented fromcutting deeper by the contact of the face 32 on the thimble with thestop face :afl'orded bythe face 12. When'thecutting is uniformlycompleted, the grinder wheel mayv be run at high speed and swung aboutover the surface of the seat to give the metal a glass-like finish. Whenthe seat is thus burnished, the motor is then stopped. During thecutting operation the face of the grinding wlieel may betrued bytraversing the dressing toolacross it by turning the screw, causing theslide to advance and retract the diamond point.

In Fig. 4 I have disclosed a modification of the centering devicewhereby the grinder may be more readily adapted to grind valves ofengines wherein the valve stem guides have been enlarged by wear or forsome other reason are not of standard uniform size.

In this modification the sleeve or bushing 11a isv not threaded upon thespindle as shown in Fig. 1' with its exterior surface of a size torotate in the valve bore, but instead the spindle 10 of the grinderrotates in the bushing and the bushing. is fitted snugly in the valvestem guide. To this end the bushing 11a is provided with a knurled heador flange 35 at its upper end and immediately below I the flange is tared through a portion of its length, the di erence in diameter at theupper and lower edges of the, tapered portion being about one-eighth ofan inch. At its lower end the diameter of the sleeve is further reducedby a tapered portion '37 terminating in a screw-threaded hub 38 andmounted on the tapered portion is a split ring 39 adapted to be expandedby means of a knurled nut 40 threaded on the hub 38. The grinder isprovided withthe micrometer thimble 13 threaded on the spindle 10 in thesame manner as in the preferred construe-- tion. I

In using this modified embodiment of the invention, a sleeve adapted todrop loosely in the valve stem'guide'will be used and the nut 40 will bescrewed upon the split ring until the latter is expanded to just fit thebore of the valve stem guide. The sleeve is then dropped in the valvestem guide and the vided, thus adapting the grinder to be fitted tovalve stem guides of'all sizes.

While I have shown and described a par- .ticular organization as my;preferred e1nbodiment of means best adapted for the grinding of largevalve seats, .Ido not wish to be understood as intending to limit myinvention there-to, since I consider such means merely as anexemplifying disclosure, and believe my invention to be capable of.practice in a diversity of forms within the scope of the appendedclaims. division of my copending application Serial No. 213,277, filedAugust 16, 1927, which has n'iatured into Patent No. 1,725,126.

I claim 1. In a machine for grinding valve seats,

This application is a the combination of a motor, a cutting wheel driventhereby, a motor support, a spindle pro ecting downwardly from the motorsupport, a cylindrical bushing adapted to fit snugly the bore of thecylinder or the like whose valve-seat is to be ground, said bushinghaving a central aperture into which the downwardly projecting-spindlefits with a sliding contact, and means for adjusting the height of themotor support relative to the valve seat comprising a ring having ascrew threaded connection with the downwardly projecting spindle andhaving its-lower face adapted to rest upon the top of the bushing tosupport the mechanism thereon, and.

means adapted to set said ring against rotat1on about the stem whilepermitting rotation of the spindlewithin the aperture of the bushing. v

2. In a machine for grinding valve seats, the combination of a motor, acutting wheel driven thereby, a motor support, a spindle projectingdownwardly from the motor support, a cyl ndrical bushing adapted to fitsnuglythe boreof thecylinder or the'like" whose valve seat is to 'beground, said bushing having a central aperture into which the downwardlypro ecting spindle fits with a sliding contact, a micrometer u on saidspindle, means adapted to set sai micrometer against rotation about saids indle while permitting rotation of the spindle within said bushing,and means adapted to limit the downward movement of the motor supportconsisting of a stop face upon said micrometer adapted to rest upon theupper end of the bushing.

v 3. In a machine for rinding valve seats, the combination of a Inishingfrictionally held within the bore of the valve stem guide v of the valveto be ground, a motor, a cutting spindle projecting wheel driventhereby, a motor support, a downwardly from the motor support an freelyslidable vertically in said bushing, and means for adjusting the heightof the motor supportrelative to the valve seat Comprising a ring screwthreaded ,u on the spindle and having its lower face a apted to restupon the top of the bushing to support the mechanism thereon, and meansadapted to set said ring against rotation about the spindle whilepermitting rotation of the spindle within the aperture of the bushing.

4. In a machine for grinding valve seats having a motor, a motorsupport, and a spindle depending from the support, a bushing on saidspindle adapted to allow the s indle to slide freely therein and adaptedto e inserted in the valve stem guide of the valve to be ground, saidbushing comprising a cylindrical body portion smaller in diameter than 1the valve stem guide, and having an exterior conical portion near thetop for engaging the top of the valve stem guide, and an expansiblecollar near the bottom for engaging the walls of the valve stem guide. 1

5. In a machine for grinding valve seats having a motor, a motorsupport, and a spindle depending from the support, a bushing on saidspindle adaptedto allow the spindle to slide freely therein and adaptedto be inserted in the valve stem guide of the valve to be ground, saidbushing comprising a cylindrical body portion smaller in diameter thanthe valve stem guide and having an exterior con-- ical portion near thetop for engaging the top of the valve stem guide, a tapered portion nearthe bottom, a split collar of resilient material mounted upon saidtapered portion, a threaded portion, on the bushing beyond said taperedportion, and a nut upon said threaded portion adjacent said split collarfor moving said collar longitudinally on .said tapered portion to varythe diameter of said collar.

In testimony whereof I afiix m signature.

' ALFRED BERG.

